不同月龄成年大鼠颈动脉零应力状态与内皮型一氧化氮合酶的关系

Effects of endothelial nitric oxide synthase on zero stress state of carotid arteries in rats of different ages

摘要:

目的：探讨不同月龄成年大鼠颈动脉零应力状态下张开角变化与内皮型一氧化氮合酶（eNOS）表达的关系。
方法：采用组织形态学方法结合计算机图像分析, 对3，6，12个月正常成年大鼠颈动脉几何形态及结构进行了形态定量学研究并检测各年龄组大鼠颈动脉血管环的零应力状态张开角；应用免疫组织化学染色技术观察不同月龄大鼠血管壁eNOS表达变化，并用eNOS底物L-精氨酸（10 mmol/L）孵育血管环30 min，观察各组大鼠颈动脉血管零应力状态张开角的变化。
结果：随着年龄增高，成年大鼠颈动脉几何形态发生明显重建，并伴有eNOS蛋白表达的降低。3,6,12个月大鼠颈动脉张开角分别为（77.9±4.2）°，（86.4±5.5）°和（110±11.2）°，6个月和12个月大鼠颈动脉的张开角都显著大于3个月的大鼠；且12个月大鼠颈动脉张开角大于6个月（P＜0.01），各组血管环给予L-精氨酸孵育30 min后，在3，6，12个月大鼠间颈动脉张开角无统计学差异，分别为（74.3±5.3）°，（79.8±6.8）°，（80.3±9.4）°。
结论：随着年龄增长，无论在血管形态学方面，还是在零应力状态方面，不同月龄大鼠颈动脉都存在着显著的差异，组织eNOS表达与正常成年大鼠颈动脉零应力状态的改变密切相关。这可能为血管移植和血管的病理改变及修复与功能重建提供了实验依据。

Abstract:

Objective：To investigate the distribution and effect of  endothelial nitric oxide synthase (eNOS) on the zero-stress state of carotid arteries in rats at different ages.
Methods：Morphometry and microstructure of carotid artery in 3-month-old, 6-month-old and 12-month-old Sprague-Dawley rats were studied quantitatively by histological method and computer image analysis. Immunohistochemistry and the NADPH-diaphorase reaction were used to localize the endothelial nitric oxide synthas (eNOS) in different age rats.  The changes of opening angle in the zero-stress state was also observed.
Results：With increasing age, there was a significant reconstruction changes in morphometric parameters and microstructure parameters of the carotid arteries in rats. While the expression of eNOS protein of endothelium and vascular smooth muscle cells were decreased. Compared with 3-month-old rats, the zero-stress state. of opening angle in 6-month-old and 12-month-old group were increased. However, pre-incubation of vessel rings with L-arginine (30 mmol/L), a substrate of eNOS,  attenuated the changes of the zero-stress state.
Conclusions：The results suggest that the carotid arterial wall in different age rats shows unequal growth and different zero-stress state eNOS may be involved in the age-related changes of zero-stress state of the carotid artery in aged rats. The results may provid an experimental base for vascular transplantation and vascular reconstruction.